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Mach's Principle
In theoretical physics, particularly in discussions of gravitation theories, Mach's principle (or Mach's conjecture) is the name given by Albert Einstein to an imprecise hypothesis often credited to the physicist and philosopher Ernst Mach. The hypothesis attempted to explain how rotating objects, such as gyroscopes and spinning celestial bodies, maintain a frame of reference. The proposition is that the existence of absolute rotation (the distinction of local inertial frames vs. rotating reference frames) is determined by the large-scale distribution of matter, as exemplified by this anecdote: You are standing in a field looking at the stars. Your arms are resting freely at your side, and you see that the distant stars are not moving. Now start spinning. The stars are whirling around you and your arms are pulled away from your body. Why should your arms be pulled away when the stars are whirling? Why should they be dangling freely when the stars don't move? Mach's princ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theoretical Physics
Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain, and predict List of natural phenomena, natural phenomena. This is in contrast to experimental physics, which uses experimental tools to probe these phenomena. The advancement of science generally depends on the interplay between experimental studies and theory. In some cases, theoretical physics adheres to standards of mathematical rigour while giving little weight to experiments and observations.There is some debate as to whether or not theoretical physics uses mathematics to build intuition and illustrativeness to extract physical insight (especially when normal experience fails), rather than as a tool in formalizing theories. This links to the question of it using mathematics in a less formally rigorous, and more intuitive or heuristic way than, say, mathematical physics. For example, while developing special relativity, Albert E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metric Tensor (general Relativity)
In general relativity, the metric tensor (in this context often abbreviated to simply the metric) is the fundamental object of study. The metric captures all the geometric and causal structure of spacetime, being used to define notions such as time, distance, volume, curvature, angle, and separation of the future and the past. In general relativity, the metric tensor plays the role of the gravitational potential in the classical theory of gravitation, although the physical content of the associated equations is entirely different. Gutfreund and Renn say "that in general relativity the gravitational potential is represented by the metric tensor." Notation and conventions This article works with a metric signature that is mostly positive (); see sign convention. The gravitation constant G will be kept explicit. This article employs the Einstein summation convention, where repeated indices are automatically summed over. Definition Mathematically, spacetime is represented by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bucket Argument
Isaac Newton's rotating bucket argument (also known as Newton's bucket) is a thought experiment that was designed to demonstrate that true rotational motion cannot be defined as the relative rotation of the body with respect to the immediately surrounding bodies. It is one of five arguments from the "properties, causes, and effects" of "true motion and rest" that support his contention that, in general, true motion and rest cannot be defined as special instances of motion or rest relative to other bodies, but instead can be defined only by reference to absolute space. Alternatively, these experiments provide an operational definition of what is meant by " absolute rotation", and do not pretend to address the question of "rotation relative to ''what''?" General relativity dispenses with absolute space and with physics whose cause is external to the system, with the concept of geodesics of spacetime. Background These arguments, and a discussion of the distinctions between absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absolute Space
Absolute may refer to: Companies * Absolute Entertainment, a video game publisher * Absolute Radio, (formerly Virgin Radio), independent national radio station in the UK * Absolute Software Corporation, specializes in security and data risk management * Absolut Vodka, a brand of Swedish vodka Mathematics and science * Absolute (geometry), the quadric at infinity * Absolute (perfumery), a fragrance substance produced by solvent extraction * Absolute infinite or Tav (number), a number that is bigger than any other conceivable or inconceivable quantity * Absolute magnitude, the brightness of a star * Absolute value, a notion in mathematics, commonly a number's numerical value without regard to its sign * Absolute pressure, the pressure in a fluid, measured relative to a vacuum *Absolute temperature, a temperature on the thermodynamic temperature scale * Absolute zero, the lower limit of the thermodynamic temperature scale, -273.15 °C * Absoluteness (logic), a concept in ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isaac Newton
Sir Isaac Newton () was an English polymath active as a mathematician, physicist, astronomer, alchemist, theologian, and author. Newton was a key figure in the Scientific Revolution and the Age of Enlightenment, Enlightenment that followed. His book (''Mathematical Principles of Natural Philosophy''), first published in 1687, achieved the Unification of theories in physics#Unification of gravity and astronomy, first great unification in physics and established classical mechanics. Newton also made seminal contributions to optics, and Leibniz–Newton calculus controversy, shares credit with German mathematician Gottfried Wilhelm Leibniz for formulating calculus, infinitesimal calculus, though he developed calculus years before Leibniz. Newton contributed to and refined the scientific method, and his work is considered the most influential in bringing forth modern science. In the , Newton formulated the Newton's laws of motion, laws of motion and Newton's law of universal g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Relativity
General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the differential geometry, geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General theory of relativity, relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time in physics, time, or four-dimensional spacetime. In particular, the ''curvature of spacetime'' is directly related to the energy and momentum of whatever is present, including matter and radiation. The relation is specified by the Einstein field equations, a system of second-order partial differential equations. Newton's law of universal gravitation, which describes gravity in classical mechanics, can be seen as a prediction of general relativity for the almost flat spacetime geometry around stationary mass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relational Theory
Relationalism is any theoretical position that gives importance to the relational nature of things. For relationalism, things exist and function only as relational entities. Relationalism (philosophical theory) Relationalism, in the broadest sense, applies to any system of thought that gives importance to the relational nature of reality. In its narrower and more philosophically restricted sense, as propounded by the Indian philosopher Joseph Kaipayil and others, relationalism refers to the theory of reality that interprets the existence, nature, and meaning of things in terms of their relationality or relatedness. In the relationalist view, things are neither self-standing entities nor vague events but relational particulars. Particulars are inherently relational, as they are ontologically open to other particulars in their constitution and action. Relational particulars, in the relationalist view, are the ultimate constituents of reality. Relationalism (theory of space and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holism
Holism is the interdisciplinary idea that systems possess properties as wholes apart from the properties of their component parts. Julian Tudor Hart (2010''The Political Economy of Health Care''pp.106, 258 The aphorism "The whole is greater than the sum of its parts", typically attributed to Aristotle, is often given as a summary of this proposal. The concept of holism can inform the methodology for a broad array of scientific fields and lifestyle practices. When applications of holism are said to reveal properties of a whole system beyond those of its parts, these qualities are referred to as emergent properties of that system. Holism in all contexts is often placed in opposition to reductionism, a dominant notion in the philosophy of science that systems containing parts contain no unique properties beyond those parts. Proponents of holism consider the search for emergent properties within systems to be demonstrative of their perspective. Background The term "holism" was coined ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karl Menger
Karl Menger (; January 13, 1902 – October 5, 1985) was an Austrian-born American mathematician, the son of the economist Carl Menger. In mathematics, Menger studied the theory of algebra over a field, algebras and the dimension theory of low-regularity (smoothness), regularity ("rough") curves and regions; as well as topology. In graph theory, he is credited with Menger's theorem. Outside of mathematics, Menger has substantial contributions to game theory and social sciences. Biography Karl Menger was a student of Hans Hahn (mathematician), Hans Hahn and received his PhD from the University of Vienna in 1924. Luitzen Egbertus Jan Brouwer, L. E. J. Brouwer invited Menger in 1925 to teach at the University of Amsterdam. In 1927, he returned to Vienna to accept a professorship there. In 1930 and 1931 he was visiting lecturer at Harvard University and the Rice University, Rice Institute. From 1937 to 1946 he was a professor at the University of Notre Dame. From 1946 to 1971, he w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benedict Friedlaender
Benedict Friedlaender (8 July 1866 – 21 June 1908; first name occasionally spelled Benedikt) was a German Jewish sexologist, sociologist, economist, volcanologist, and physicist. Life Friedlaender was born in Berlin as the son of Carl Friedlaender (1817–1876), a professor of economics. His grandfather was Nathan Friedlaender (died 1830), a Berlin physician and university lecturer. Among his siblings was Immanuel Friedlaender (1871–1948), a distinguished volcanologist. He studied mathematics, physics, botany, and physiology in Berlin, earning a Ph.D. in zoology in 1888. As a well-to-do donor, he supported the anarchist journal ''Kampf'' and published in the journal ''Der Sozialist''. He gave substantial financial support to Magnus Hirschfeld's Scientific-Humanitarian Committee (Wissenschaftlich-humanitäres Komitee, or WhK) in Berlin. The primary goal of the WhK was to work against Paragraph 175 of the Imperial Penal Code, which criminalized "unnatural vice" between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Berkeley
George Berkeley ( ; 12 March 168514 January 1753), known as Bishop Berkeley (Bishop of Cloyne of the Anglican Church of Ireland), was an Anglo-Irish philosopher, writer, and clergyman who is regarded as the founder of "immaterialism", a philosophical theory he developed which was later referred to as "subjective idealism" by others. As a leading figure in the empiricism movement, he was one of the most cited philosophers of Age of Enlightenment, 18th-century Europe, and his works had a profound influence on the views of other thinkers, especially Immanuel Kant and David Hume. Interest in his ideas increased significantly in the United States during the early 19th century, and as a result, the University of California, Berkeley, as well as the city of Berkeley, California, were both named after him. In 1709, Berkeley published his first major work ''s:An Essay Towards a New Theory of Vision, An Essay Towards a New Theory of Vision'', in which he discussed the limitations of huma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Closed Timelike Curve
In mathematical physics, a closed timelike curve (CTC) is a world line in a Lorentzian manifold, of a material particle in spacetime, that is "closed", returning to its starting point. This possibility was first discovered by Willem Jacob van Stockum in 1937 and later confirmed by Kurt Gödel in 1949,Stephen Hawking, '' My Brief History'', chapter 11 who discovered a solution to the equations of general relativity (GR) allowing CTCs known as the Gödel metric; and since then other GR solutions containing CTCs have been found, such as the Tipler cylinder and traversable wormholes. If CTCs exist, their existence would seem to imply at least the theoretical possibility of time travel backwards in time, raising the spectre of the grandfather paradox, although the Novikov self-consistency principle seems to show that such paradoxes could be avoided. Some physicists speculate that the CTCs which appear in certain GR solutions might be ruled out by a future theory of quantum gravity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
